The bone tissue is composed of bone matrix and bone cells. Bone matrix comprises mainly type I collagen as well as other proteins, including osteocalcin and osteonectin. These and other proteins take part in matrix maturation, mineralization and may regulate the functional activity of bone cells, the latter being primarily osteoblasts and osteoclasts. Osteoblasts are bone-forming cells and osteoclasts are bone resorbing cells. The main function of the bone cells is to mediate bone remodeling mechanisms in order to maintain the integrity of the skeleton by removing old bone of high mineral density and high prevalence of fatigue microfractures through repetitive cycles of bone resorption and bone formation. During bone formation phase, the osteoblasts are recruited from stem cells population present in bone marrow.
There are two main populations of stem cells in the bone marrow: hematopoietic stem cells (HSC), which give rise to all blood cell lineages including erythrocytes, platelets, and white blood cells), and mesenchymal stem cells (MSC). The MSC are self-renewing, clonal and multipotent precursors of nonhematopoietic tissues, capable of differentiating into osteoblasts, chondrocytes, astrocytes, pneumocytes, hepatocytes, neurons, and cardiac myocytes.
Bone marrow-derived stem cells (BMSCs) contribute to tissue repair or regeneration of a broad spectrum of tissues including myocardium, cardiac valves, blood vessels, damaged bone, simple bone cysts, and fracture delayed union or non-union tendon, cartilage, 2 meniscus, and skin. Bone marrow aspiration can be obtained from any of the standard autograft locations, e.g., iliac crest, proximal/distal tibia, or calcaneus. Standard technique for BM aspiration is withdrawal of the later using a suitable needle, such as trocar or bone marrow biopsy needle and an anticoagulant-containing syringe.
PRP is a product of blood plasma that is rich in platelets. PRP may be used in a variety of therapeutic or cosmetic applications including enhancing wound healing in dental implants and sinus elevations, heart surgery, orthopedic surgery, and dermatology (chronic wound healing) [Barry L. et al, Plastic Reconstructive Surgery 114(6): pp. 1502-1508, 2004; Barry L. et al, Plastic Reconstructive Surgery 118(6): 147e-15, 2006; and Kajikawa Y. et al, J. Cell Physiol., 215(3): pp. 837-45, 2008; and Jacques Otto (published online: http://www.theottoclinic.ie/skin_rejuvenation.htm). PRP may also be utilized as a culture medium for cell expansion in the laboratory.
WO2005/065269 discloses several compositions comprising PRP and fibroblast cells for the treatment of skin, in particular, repeated administration of PRP in a dermatologically acceptable carrier to skin to e.g. reduce appearance of wrinkles.
Thus there is a long unmet need to provide methods and means to obtain PRP, MSC and BMSC, in a state ready for use in therapeutic or cosmetic applications or procedures.